Auditory P300 and eye tracking dysfunction in schizophrenic pedigrees

Several psychophysiological abnormalities associated with schizophrenia have been proposed as genetic trait markers of vulnerability to the disorder. Smooth pursuit eye tracking dysfunction and abnormal long latency event-related potentials are the most promising candidates. Both are independent of the effects of psychotropic medication or mental state at the time of testing, and twin studies demonstrate that each has a high level of heritability. Having recorded smooth pursuit eye tracking and event-related potentials in 20 high-density schizophrenic families, we find abnormalities in one or both measures in most of the families studied. The abnormalities, when present, occur in the family members with schizophrenia and other forms of functional psychosis, and they have a bimodal distribution with approximately half the nonschizophrenic relatives also showing eye tracking dysfunction and/or abnormal event-related potentials. Some of these relatives had psychiatric symptoms; others were normal. Our results suggest that psychophysiological examination can help to clarify the boundaries of schizophrenia spectrum disorder. By helping to decide the phenotypic status of nonschizophrenic family members, this should increase the power of DNA linkage studies.     

NMDA receptor activation during epileptiform responses in the dentate gyrus of epileptic patients.

We previously showed that a low frequency (1 Hz) train of perforant path stimulation evokes burst discharges in the dentate gyrus of hippocampal slices obtained from patients surgically treated for intractable temporal lobe epilepsy. We report here that multiple population spikes that characterize the burst discharge are blocked reversibly by the specific NMDA receptor antagonist, D-(-)-2-amino-5-phosphonovaleric acid (D-APV). The epileptiform discharge evoked in human dentate gyrus by stimulation trains of 1 Hz could be reproduced in the rat dentate gyrus in vitro by the same stimulation protocol but required the presence of low concentrations (0.2-0.6 mM) of extracellular magnesium. We suggest that low frequency orthodromic stimulation of dentate granule cells through the perforant path progressively evokes an increase in the activation of NMDA receptors resulting in burst discharges in tissue from epileptic patients.     

Solitary infantile myofibromatosis

Infantile myofibromatosis is an uncommon, benign, probably hamartomatous proliferation of myofibroblasts. Its growth is typically self-limiting but histologically it can simulate a sarcoma. A rare case of solitary infantile myofibromatosis presenting as an intraoral mass in a 10-year-old girl is reported.     

Deep venous thrombosis in the surgical intensive care unit

The ICU patient population is at a high risk for the development of deep venous thrombosis leading to a potentially fatal pulmonary embolism. It is vital to appreciate this risk and apply appropriate prophylaxis. Constant vigilance is required, as deep venous thrombosis and pulmonary emboli can develop and progress despite standard prophylactic measures. In unstable patients, more aggressive prophylaxis may be warranted, including the use of inferior vena cava filters. A high index of suspicion and a low threshold for screening and diagnostic testing will allow earlier recognition and treatment of this lifethreatening condition. Treatment decisions are based on clinical suspicion, diagnostic examination results, and the potential complications of difficult treatment modalities.     

CEEG mapping in drug-free schizophrenics. Differences from healthy subjects and changes induced by haloperidol treatment.

A topographic CEEG investigation was carried out in 20 drug-free, DSM-IIIR diagnosed schizophrenics and in a group of matched healthy controls. The effects of acute and chronic haloperidol treatment were then assessed in the patient group. On the baseline recording, schizophrenics showed a widespread increase in delta, theta 1 and beta 3 amplitude. Acute haloperidol administration produced a decrease in delta and an increase in slow beta amplitude. After 28 days of treatment, delta and fast beta were reduced while theta 2 and alpha 1 were increased. CEEG abnormalities in schizophrenic subjects appear, therefore, to be reduced by chronic neuroleptic treatment.     

Risk factors and their relation to initiation of alcohol use among early adolescents

This study examined the relationship between risk factors and initiation of alcohol use over a 15-month period among a cohort of 7th graders who were abstainers at the time of initial testing. The relationship between risk factors and alcohol use was examined using a discriminant function analysis. At the univariate level, rejection of parental authority, deviant behavior, and sensation seeking were statistically significant. The discriminant function retained only three of the risk factors: rejection of parental authority, deviant behavior, and religious commitment. Implications for school-based prevention programs are discussed, particularly the need to target primary prevention programs based upon adolescents' risk.     

Thyroid stimulating hormone response to thyrotropin in prepubertal depression

In an effort to evaluate whether differences exist in the hypothalamic-pituitary-thyroid axis of depressed children, a thyrotropin releasing hormone (TRH) stimulation test was administered to 55 prepubertal subjects who were divided into three groups matched for age and sex: a depressed group (endogenous N = 15, nonendogenous N = 15), a psychiatric nondepressed control group (N = 16), and a normal control group (N = 9). Each subject was tested at two dosages of TRH, 2 micrograms/kg and 7 micrograms/kg. Increasing age and female sex were positively correlated with a greater thyroid stimulating hormone (TSH) response. TSH response to TRH was examined with subjects reclassified by severe suicidal ideation, severe aggression, and parental history of alcoholism. Results of this study are contrasted with the adult psychiatric literature.     

Tachykinin receptor cross-talk. Immunological cross-reactivity between the external domains of the substance K and substance P receptors.

In the present study, we have chemically synthesized peptides which correspond to the four putative extracellular domains of the predicted substance K (SK) receptor protein and raised specific polyclonal antibodies against these peptides. These antibodies were then tested for both structural and functional recognition of epitopes on the substance P (SP) receptor on rat AR42J pancreatic cells and human IM9 lymphoblasts, which express the SP receptor, but not the SK receptor. Antibodies directed against the first, second, and fourth external domains of the predicted SK receptor recognized a 58-kDa protein on AR42J cells. This protein has a molecular weight similar to the previously demonstrated SP receptor on both AR42J cells and IM9 cells. Furthermore, antibodies against the second and fourth extracellular domains significantly inhibited specific 125I-SP binding on both AR42J and IM9 cells, and also significantly inhibited SP-induced mobilization of [Ca2+]i on AR42J cells. These data suggest that the second and fourth extracellular domains of the SK and SP receptors may share common structural motifs for ligand binding and signaling mechanism.